| Sensitization of TNFα and Agonistic FAS/CD95 Antibody-Induced Apoptosis by INFγ on Neuroblastoma Cells |
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Ho Il Bang, Jong Duck Kim, Du Young Choi |
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Department of Pediatrics, School of Medicine, Wonkwang University, Iksan, Korea |
| 신경모세포종에서 IFNγ에 의한 TNFα와 길항적 FAS/CD95항체 유도성 세포고사의 감작화 |
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방호일, 김종덕, 최두영 |
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원광대학교 의과대학 소아과학교실 |
Correspondence:
Du Young Choi, Email: CDY8118@wonkwang.ac.kr
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| Abstract |
Purpose
: IFNγ sentitizes many tumor cells to TNFα and FASL-mediated apoptosis by enhancing the expression of TNF or FAS/CD95 receptor and modulating the activation of caspase and Bcl-2 family. It has been reported that IFNγ and TNFα synergistically caused differentiation and growth inhibition of neuroblastoma cells. Even though some neuroblastoma cell express FASR/FASL on the cell surface, they could not induce apoptosis by ligation of the FAS/CD95 receptor. But the treatment of IFNγ is reported to induce apoptosis in some neuroblastoma cell lines through the CD95/ CD95L autocrine circuit. In this study, we examined whether IFNγ could affect TNFα and agonistic FAS/CD95 antibody(CH-11)-induced apoptosis against neuroblastoma cell lines that had shown diverse drug sensitivity and resistance.
Methods
: CHLA-15, CHLA-90 and LA-N-2 neuroblastoma cells were cultured in IMDM and treated with recombinant IFNγ, TNFα and CH-11 antibody. Cell viability was measured by DIMSCAN with a fluorescent calcein-AM. Apoptosis was analyzed through flow cytometry using Annexin V- PE and 7-ADD staining and confirmed by pancaspase and caspase-8 blocking experiments. The expression of TNF RI and FAS/CD95 receptor was evaluated by flow cytometry using the corresponding antibody and PE-conjugated secondary antibody.
Results
: IFNγ or TNFα alone had no demonstrable cytotoxic effects, whereas both cytokines in combination induced apoptosis synergistically in CHLA-15 and CHLA-90 cells. Although there was no cytotoxicity with the ligation of CH-11 alone in CHLA-90 cells, pretreatment of IFNγ increased the sensitivity of CH-11-mediated apoptosis. The expression of TNFRI and FAS/CD95R were nonspecifically enhanced after treatment of IFNγ without relation to sensitivity to TNFα and CH-11. This finding suggest up-regulation of both receptors may contribute to sensitization of TNFα and CH-11-mediated apoptosis by IFNγ in only sensitive cell lines.
Conclusion
: IFNγ induced sensitization of TNFα and agonistic FAS/CD95 antibody-mediated apoptosis on some neuroblastoma cells through up-regulation of TNFRI and FAS/CD95 receptor. |
| Key Words:
Neuroblastoma, IFNγ, TNFα, Agonistic FAS/CD95 antibody(CH-11) |
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